Last



G. P. S. CROSS Sept. 28, 1937.

Patented Sept. 28, 1937 Z,0%,li8

Garrett P. S. Cross, Beverly, Mass, assignor to United Shoe Machinery Corporation, Paterson, N. 3., a corporation of New Jersey Application June 25,

6 Claims.

This invention relates to hinge lasts of the impositive lock type. Lasts of this type have a heel part and a forepart hinged. together to permit a relative rotary movement between the parts in order to collapse the last. They are also provided with a bonding mechanism between the parts which yields to pressure when the last is to be collapsed, but tends to restore the last parts to I the positions from which they have been moved,

10' at least until the movement has reached a sub stantial magnitude. Many such lasts resiliently resist movement from either extended or collapsed position, and it is such a last that is disclosed herein.

1"5 A number of lasts of this character have been provided with a resilient link connection between the last parts. Ordinarily this link joins two pins, one in each last part, and the center around which the last parts swing in collapse lies a little to one side of the line joining the centers of the pins so that when the last is collapsed the line passes over the center, the two last parts acting as toggle links. The collapsing movement causes the pins to separate a little, initially, thus stretching the resilient link until the dead center position is reached, and a slight movement either way from the dead center position will be automatically continued by the resilient action of the link, until fully extended or collapsed position is reached. In the same way the last automatically resists movement from either such position. Since the resilient link in such a last has to be very strong, the amount of stretch necessary in operating the last must be small in order to permit operation of the last by hand, as is customary in shoemaking. Therefore the center of retation of the last parts must not be far from the axis of the link, when the last is extended, in order to derive maximum advantage from the toggle action.

Lasts of this type have given difficulty when they are supported on their upper sides at the heel and toe and treated with pressure on the bottom, as in the leveling machine. The last parts then tend to rotate about the lower edges of the joint surfaces at which they are in contact, and such rotation, if it takes place, will stretch the link in the same Way as above described in reference to the collapsing operation. The leveling pressure is often severe enough to effect a substantial overstretching movement of this kind, of sufficient magnitude to distort a shoe on the last, or to damage the last.

It has been proposed to alleviate this difficulty by mounting an inextensible link alongside the 1936, Serial No. 87,245

resilient link, the extensible link having slotted ends to permit the pins to separate just enough to collapse the last, such separation being quite small, as above suggested. When the backward collapsing movement in the leveling machine be- 5 gins, the inextensible link brings up firmly on the pins before any substantial movement has taken place, and rigidly holds the last against further movement of this sort. Such lasts are expensive because of this extra link, and labor cost in as- {5 sembling.

The principal object of the present invention is to provide a last having the advantages of the type of last just described, but which is not subject to the objection of added expense and com- 3 plication. The resilient link according to the present invention is provided in itself with means to prevent its own overstretching, so that no extra parts are required. Conveniently, and as shown in the last herein illustrated, the link is 15 formed in a generally elliptical shape, with its longer axis extending between the pins, so that the middle positions of its longer sides are brought closer together by the longitudinal stretching due to either of the movements dis- 20 cussed above. The means for preventing overstretching the link is shown as a lug or abutment on the inside face of the long side of the link which abuts against a surface on the opposite side of the link when the pins separate a little 25 more than they have to do in the collapsing movement. As soon as this contact takes place, the link becomes inextensible unless sufficient force to break the last is applied.

These and other features of the invention com- 30 prising certain combinations and arrangements of parts will be apparent from the following description of a preferred embodiment of the invention shown in the drawing, in which Fig. 1 shows the last in extended position;

Fig. 2 shows the last in collapsed position; and

Fig. 3 shows the action of the link in preventing backward collapse.

The illustrated last consists of a forepart l0 and a heel part i2 separated by a cut comprising a V-shaped opening it and a knuckle [6, as is well known in lasts of this character. The center it of the knuckle is the axis of the collapsing movement. The bonding mechanism comprises an open oval-shaped resilient link 28, which joins pins 22, 26, one in each of the last parts. As exaggeratedly shown in Fig. l, the center it is a little above the axis 28 of the link 2% so that the pins separate slightly in collapse and the link is correspondingly stretched, until the axis 26 passes to the other side of the center [8 (Fig. 2). Until the axis 26 of the link crosses the center I8 the last parts tend to return to the position from which they have been moved, either extended or collapsed.

The central part of the link 2!] is provided with two opposed lugs 28, one on each side. The lengths of these lugs 28 are such that they do not quite touch when the last is extended or collapsed (Figs. 1 and 2), or in any intermediate position. When the last is stressed in such a way as to bend it backwards, as is exaggeratedly shown in Fig. 3, only a very slight rotary movement about the point 30 can take place before the lugs 28 come firmly together (Fig. 3). Such movement is considerably less than the movement involved between the extended (or collapsed) position and the dead center position because the point 30 is considerably farther from the axis 26 of the link than is the center l8, and a correspondingly smaller rotary movement about the point 36 will stretch the link to its limit, where the lugs 28 render it substantially rigid.

The bonding mechanism described above consists of only three members, one link and two pins, and is correspondingly cheap, easy to. assemble, and simple and effective in operation.

Having described my invention, What I claim as new and desire to secure by Letters Patent of the United States is:

1. A hinge last comprising a heel part and a forepart arranged for relative rotation about an axis fixed in the last, a resiliently extensible link joining said last parts, and means on the link to prevent overstretching thereof.

2. A hinge last comprising a heel part and a forepart arranged for relative rotation about an axis fixed in the last, a resiliently extensible link pivotally joining said last parts, the longitudinal axis of the link lying between the first said axis and the tread face of the last, and means on the link to prevent stretching thereof substantially beyond the extent necessary to permit collapse of the last.

3. A hinge last comprising a heel part and a forepart arranged for relative rotation about an axis fixed in the last and a resiliently extensible oval-shaped open link joining said last parts, the longitudinal axis of the link lying between the first said axis and the tread face of the last, said link having a lug on the inside face of one of its longer sides arranged to contact with a surface on the opposite longer side before the link has been stretched substantially to a greater extent than that involved in collapsing the last.

4. A resiliently extensible link for a hinge last, said link being of open oval shape with its long axis lying in the direction of extension and having a lug on one of the inner faces of its opposite longer sides, said lug terminating adjacent to a surface on the inner face of the opposed longer side.

5. A resiliently extensible link for a hinge last, said link being of open oval shape and having opposed lugs on the inner faces of its opposite longer sides, said lugs having a free space between them sufficient to permit stretching the link only to the desired amount.

6. A resiliently extensible link for a hinge last, said link being of open oval shape with its long axis lying in the direction of extension and having opposed lugs on the inner faces of its opposite 35 longer sides.

GARRETT P. S. CROSS. 

